I must admit I have never met the message (and situation) like that. If the data held on your droplet is crucial, I recommend you to contact DO support team, and to not perform any action unless they instruct you to do that.
But, let’s assume that your data is backed up, and you have nothing to loose. So, what I would do, is:
1. Using DO control panel take a snapshot of the droplet, just in case.
2. In control panel switch to recovery environment (Boot from Recovery ISO), and launch recovery console.
3. From the menu choose Check Filesystem. Some messages should be displayed then. Note from them what is your file system, for further purposes.
4. Shutdown recovery environment, in control panel switch to your regular droplet’s environment (Boot from Hard Drive), and turn the droplet on.
5. If the problem still persists, switch to recovery console again to use more powerful filesystem checking tool.
6. From the menu choose Interactive Shell.
7. Let’s assume that your droplet’s filesystem is XFS (as it is in Centos 8 droplet). You could figure out the filesystem type when you did Check Filesystem in step 3.
8. To find out what is your droplet’s disk, execute command
It will be a message displayed, looking like that:
Disk /dev/vda: 25 GiB, 26843545600 bytes, 52428800 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: gpt
Disk identifier: 8A5128D6-37BC-4C45-918E-A322C04589E1
Device Start End Sectors Size Type
/dev/vda1 6144 52428766 52422623 25G Linux filesystem
/dev/vda2 2048 4095 2048 1M BIOS boot
Find the section of a disk which size equals your droplet’s size. In above case it is /dev/vda1
9. Run xfs_repair utility. This utility is intended for XFS filesystem only. If your droplet’s disk have different filesystem than XFS, you have to use the other utility.
Accordingly to above, examplary configuration, it would be:
10. When filesystem checking is finished, shutdown recovery environment, switch to your regular droplet’s environment, and turn the droplet on.
11. Check if droplet works correctly. Update us with the current situation :-)